1. Field of the Invention
This invention has relation to a jig for holding rotary lawnmower blades for sharpening.
2. Description of the Prior Art
It is known to provide an adjustable blade holder that pivots about a guide rod to provide a desired bevel angle for sharpening a blade. See U.S. Pat. No. 3,574,268 issued to Buse in April of 1971.
Other devices for sharpening lawnmower blades are found in the following patents which do not show the claimed features of the present invention. U.S. Pat. No. 4,265,146 issued to Horrell in May of 1981; and U.S. Pat. No. 3,061,980 issued to Machovec in November of 1962.
What was needed before the present invention was a blade holder which could produce precisely angled cutting edge portions on lawnmower blades and then could produce identically beveled cutting edges on identically shaped cutting edge portions symmetrically situated at opposite ends of rotary lawnmower blades.
Additional patents found in a search for this invention show structures for grinding other implements, but none provide for precisely positioning and repositioning the blade to be ground symmetrically at both ends. These patents are:
______________________________________ U.S. Pat. No. Inventor Issued ______________________________________ 4,528,778 Wolff July 1985 3.054,229 Peasley et al. September 1962 2,888,965 Phillips June 1959 2,589,165 Toy et al. March 1952 1,915,247 Holloway et al. June 1933 ______________________________________